U.S. Pat. No. 5,301,798, granted Apr. 12, 1994, to A. L. Wilkens, discloses extruded thermoplastic floor slats that fit down over thermoplastic resin slide bearings which are attached to guide beams. The material from which the floor slats are made is apparently homogenous throughout the structure of the slats. U.S. Pat. No. 4,896,761, granted Jan. 30, 1990, to the present applicant, discloses a metal floor slat that snaps down onto a plastic bearing which is installed on a guide beam. The slat has a side groove which receives and retains an inboard base portion of an elongated seal strip. The outboard end of the seal strip engages the side of an adjacent floor slat. U.S. Pat. No. 4,984,679, granted Jan. 15, 1991, to the present applicant, discloses an arrangement similar to U.S. Pat. No. 4,896,761 with the additional feature of a two-material seal strip. The inboard portion of the seal strip is relatively resilient and provides a cushion backing. The outboard portion that engages the side of the adjacent slat is formed from a plastic material that is relatively hard and has a relatively low coefficient of friction. The patent also discloses a co-extrusion procedure for making the two-material seal strip.